Cell cultures from the fetal mammalian central nervous system were used to study the regulation of neurodevelopment by neuropeptides, trophic factors and electrical activity. Vasoactive intestinal peptide was shown to increase the number of astorcytes during development in culture. Radioligand binding studies on whole cell and membrane preparations of astrocytes indicated the presence of high affinity receptors for VIP. Inositol phospholipid turnover was shown to be increased in astrocytes after stimulation with norepinephrine and bradykinin, but not with VIP treatment. Viral pentapeptides (TTSYT and TINYT) with sequence homology to VIP(7-11) were shown to exhibit VIP-like increases in neuronal survival during electrical blockade. Feasibility studies using DEAE sephacel, affinity column (wheat germ agglutinin, Concanavalin A and heparin), and Amicon filtration indicated that an activity-related neuron survival factor and a choline acetyltransferase (CAT)-stimulating factor did retain biological activity through these separation procedures. A number of possible sources for the factors have been found and potential second messenger systems have been identified. The survival of spinal cord neurons was shown to be influenced by NMDA antagonists. Activity blockade with TTX and the GABAergic agonist muscimol were shown to produce a reversible and developmentally sensitive decrease in the cells immunoreactive to methionine-enkephalin in spinal cord cultures.